With the advance of modern science and computer technology, the information exchange between human beings and computers is becoming more important. Traditional way of such communication is via a keyboard for input, and via a display or printer for output. When inputting Chinese characters, one needs to remember the coding scheme, which is very inconvenient. If a computer can have the ability of communicating through speech like human beings, then a dialog based on voice would be possible. This will change the man-machine communication fundamentally, and the overall efficiency of information processing will be greatly increased. Presently, with the great efforts of computer scientists, different types of speech recognition systems, and in particular, Chinese speech recognition systems, have been developed.
Since a Chinese character generally has several homonyms and near homonyms, existing Chinese speech recognition systems rely on word, phrase, and higher language level information to resolve the ambiguities in Chinese characters. One generally uses an acoustic model to determine what is the most likely character according to the inputted syllable, and also uses the dictionary with probabilities and the language model where stores the higher level pattern of language usage to resolve the ambiguity of Chinese characters.
However, the recognition of a single Chinese character out of context is very difficult, and typically it may be recognized as any one of a set of characters with same of similar pronunciations. In particular, when inputting Arabic numerals or isolated English alphabets into a Chinese speech recognition system via voice, there is no way to distinguish them from Chinese characters which have the same or similar pronunciations. Generally speaking, Chinese speech recognition systems are typically not trained to recognize English alphabets, and people may pronounce English alphabet letters quite differently.
In summary, a method for reliably recognizing alpha-numeric sequences in a Chinese speech recognition system is needed.